335
FXUS66 KMTR 081942 CCA
AFDMTR

Area Forecast Discussion...CORRECTED
National Weather Service San Francisco CA
1242 PM PDT Wed May 8 2024

...New SYNOPSIS, SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 1241 PM PDT Wed May 8 2024

Warming trend begins today  with the warmest temperatures expected
Thursday and Friday. Offshore winds continue through Thursday with a
Wind Advisory in effect for the North Bay interior mountains through
Thursday morning. A slight cooldown will begin this weekend and
continue into the early part of next week.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 1241 PM PDT Wed May 8 2024

Summary:

* Warming trend begins today and peaks Thursday and Friday
* Minor HeatRisk throughout the region, Moderate HeatRisk in the
  interior Bay Area
* Breezy northerly winds continue today
* Wind Advisory for the North Bay interior mountains through 8 AM
  Thursday
* Gradual cooldown begins this weekend through early next week

The warmup has begun as temperatures across the region are generally
running around 5 to 10 degrees above the same time yesterday. A
ridge is building over the eastern North Pacific, building into
British Columbia and the Pacific Northwest through the next couple
of days. At the same time, an upper level low centered over the
northern Plains is elongating along a generally east-west axis, the
trough regressing into the Great Basin and breaking off into a weak
cut-off low. The combination of these two systems is leading to
north to northeast flow aloft, a situation that generally leads to
warmer temperatures in the area.

Forecast highs are generally reflecting today`s warming trend, with
interior locations seeing highs into the lower 80s, the Bayshore
seeing highs in the upper 70s, and mid to upper 60s expected along
the coast. Breezy north winds continue to develop with wind gusts up
to 20-25 miles per hour across the valley regions. The higher
elevations, especially in the North Bay, are in a lull through the
afternoon, but gusts up to 45 to 55 miles per hour are expected to
resume later this evening and continue through Thursday morning.
Thus, the Wind Advisory for the North Bay interior mountains
continues through 8 AM on Thursday.

Overnight lows will be quite warm across the Bay Area, with
temperatures on Thursday morning in the mid to upper 50s. The
Central coast will see somewhat cooler lows overnight in the upper
40s to low 50s. The heat event starts to peak on Thursday, with
interior highs in the mid to upper 80s and coastal highs in the low
to mid 70s. Of note, downtown San Francisco is currently expected to
reach 81 on Thursdsay; if the forecast verifies, it would be the
first 80-degree day in the city since last October. Winds are
expected to diminish through the day Thursday.

This section from yesterday continues to apply today: The seasonably
warm temperatures are causing a minor to moderate HeatRisk, meaning
that a low to moderate risk for heat related illnesses exists for
vulnerable populations (children, the elderly, pregnant women, or
those without adequate shelter or cooling), with moderate HeatRisk
values concentrated in the interior regions of the North, East, and
South Bays.

With the significant warm up expected for the rest of the week,
here`s a reminder of some heat safety tips:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 1241 PM PDT Wed May 8 2024

Friday will be the second day of the peak heat event, and while
areas closer to the coast might see temperatures drop by a few
degrees, the interior areas should expect temperatures to rise even
further, as high as the lower 90s in the warmest locations. Cooling
begins Saturday, as a decaying ridge allows onshore flow to reassert
itself. Coastal regions will see the most cooling, and by Sunday,
should return to seasonal temperatures for this time of year
(generally, the low to mid 60s). At the same time, the interior will
continue to see highs in the low to mid 80s, warmer than the
seasonal average, through the early part of next week. Ensemble
models and clusters are showing that another ridge approaches the
West Coast next week, which could help maintain temperatures above
the seasonal averages. CPC products are showing temperatures above
seasonal averages continuing into the third week of May.

&&

.AVIATION...
(18Z TAFS)
Issued at 1044 AM PDT Wed May 8 2024

VFR through taf period. As mentioned with previous taf package,
biggest impact to terminals the next 24-36 hours will be the
winds. While surface winds will be breezy at times there will be
bursts of offshore flow, especially tonight. The gusty offshore
flow 2000-2500 ft will lead to lower end LLWS for the N Bay, E
Bay, and SF Bay.

Vicinity of SFO...VFR...N to NW flow with gusts 25-30 kt through
this evening. Easing at the surface tonight as offshore (NE)
increases aloft with some LLWS.

SFO Bridge Approach...similar to SFO.

Monterey Bay Terminals...VFR. Similar to this morning a few patchy
cigs may be over MRY Bay Thursday AM.

&&

.MARINE...
(Today through Monday)
Issued at 908 AM PDT Wed May 8 2024

High pressure to the north and low pressure to the south will
maintain moderate to locally strong northerly winds over the
coastal waters and bays through tonight. The stronger northerly
winds will result if fresh steep swell today. By Friday, winds
are largely light to moderate across much of the waters. Wave
heights gradually diminish to around 5 to 7 feet by late week. Dry
weather continues through the forecast period as high pressure
dominates.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 8 AM PDT Thursday for CAZ504.

PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of
     Bay Bridge.

     Small Craft Advisory until 9 PM PDT this evening for Mry Bay-Pt
     Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
     to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Gale Warning until 3 PM PDT this afternoon for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...MM
MARINE...MM

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